Cromolyn (also known as cromoglicic acid, cromoglycate, or cromoglicate) has been approved previously for use in asthma. Its approved form is available as a disodium salt form, cromolyn sodium (also known as disodium cromoglycate or DSCG). Cromolyn demonstrates poor oral absorption. Delivery of cromolyn via inhalation has proven inefficient and difficult due, at least in part, to the hygroscopic nature of cromolyn sodium. For example, micronized powders containing cromolyn sodium particles spontaneously absorb water, forming clumps that impair efficient delivery of the cromolyn powder. See Keller et al. Expert Opin. Drug Deliv. 8, 1-17 (2011). Additionally, the performance and the efficiency of previously used inhalers are highly dependent upon a patient's inspiratory flow rate, leading to a wide variability in the amount of cromolyn sodium that is delivered to a patient. See Richards et al., Journal of Pharmacology and Experimental Therapeutics, 241, 1028-1032 (1987).
The present invention provides improved compositions and methods for delivering cromolyn via inhalation, efficiently and consistently over a range of inspiratory flow rates.